Postoperative complications and mortality: Are they unavoidable?

Abstract

As surgery inherently involves injury to the human body as a result of its invasive nature, it may result in postoperative complications. 1 Further, in patients who do not recover from the morbidity, worsening of their condition could ultimately result in mortality. Although numerous efforts have aimed at reduction in surgical mortality, zero postoperative mortality has been achieved in only a very limited number of hospitals. Most of the reports of zero mortality involved retrospective studies in single centers. However, as the results of small studies are believed to be less reliable, it is difficult to explore universal best practices. Furthermore, even a hospital that has achieved zero postoperative mortality at some point, might encounter operative death at a later date owing to expansion of operative indications. Therefore, the results of risk analysis carried out at a particular hospital often may not be valid in other hospitals. Recently, several multicenter nationwide cohort studies on risk factors for operative morbidity and mortality, consisting of over thousands of patients, have been published. In Japan, an extensive nationwide database of clinical factors from surgical patients (National Clinical Database [NCD]) was launched in 2011. This database covers about 1.2 million cases a year, accounting for approximately 95% of general surgical cases. 2 The total number of cases accumulated exceeds 4 million cases from 3745 hospitals. 3 A total of 1 494 934 cases underwent 115 types of gastroenterological surgeries from 2011 to 2013. The 30-day mortality was 1.5% (n = 22 334), and 90-day mortality was 2.8% (n = 42 048). Of them, 14 000 patients died of postoperative complications per year. In addition, several nationwide database studies have been reported, such as that of the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP). 4 Such studies have provided much reliable information from all over the world on risk analysis for postoperative complications and deaths, which is difficult to obtain from single-center retrospective studies. Surgical morbidity rates vary according to the type of procedure (Table 1). 5-23 The lowest morbidity rate of 5.6%-7.2% was observed with laparoscopic cholecystectomy for acute cholecystitis, whereas the highest rate of 54.4% was observed with pancreaticoduodenectomy (PD). Operative mortality showed the same tendencies. The lowest mortality of 0.4%-0.5% was seen with laparoscopic cholecystectomy, and the highest with esophagectomy, hepatectomy and PD. 6,17,21,22 Interestingly , mortality rates were approximately one-tenth the morbidity rates for most operative procedures. The fact that one-tenth of patients with morbidities show a decline in their condition, resulting in death, might imply hidden factors related to vulnerability to surgical stress, such as single nucleotide polymorphisms (SNP) of inflammatory cytokines, neu-trophil activation, and immunoglobulins. Elderly patients have double the rate of postoperative complication/mortality ratio than non-elderly patients (20.1% vs 10.8%) 14 (Table 1). This disparity in mortality may indicate that elderly patients are at greater risk for difficulty of recovery from severe complications. However, low anterior resection for rectal cancer represents a deviation from the above-mentioned "10% rule". Its morbidity and mortality rates in the NCD study were 26.3% and 0.9%, respectively. The ACS NSQIP also indicated a similar tendency, with a morbidity of 30.1% and a mortality of 1.1%. 6 This may be explained by the use of diverting ileo-or colostomy, a potentially effective evacuation of severe abdominal abscess as a result of anastomotic leakage. Numerous risk factors for postoperative morbidity and mortality have been reported, which can be broadly classified as patient factors (age, Charlson comorbidity score, hypoalbuminemia etc.), therapeutic factors (preoperative chemotherapy, blood transfusion etc.), and hospital factors (number of operative cases, participation of board-certified surgeons etc.). With regard to hospital factors, quality of perioperative care is associated not only with the skill of the surgeon, but also with that of other medical staff. Recovery from postoperative complications, in particular, involves a comprehensive